At present, with the development of society and the gradual improvement of people's living standards, earphones have become indispensable peripheral audio devices in modern electronic systems (such as mobile phones, tablets, and etc.). In-ear earphones stand out from many types of earphones because of the features of being easy to carry and having a fashionable appearance. The in-ear earphones are favored by more and more consumers, and are applied in more and more industries and fields, and the in-ear earphones have gradually become a trend in the earphone industry.